I am having lap siding installed on my house. There is z flashing above all windows and the garage. The seam between the flashing and the siding, the top of the horizontal portion of the z flashing, has been caulked. Looking at the installation instructions of the siding (figure 7 page 2, http://www.jameshardie.com/pdf/install/hardieplank-hz5.pdf ) it states not to caulk this area. The contractor already caulked this area. What are the risks of having the caulk there?
Its a common sense thing really. Flashing exists to ensure water or condensation that enters above an opening is conducted back to the outside. When the outlet is blocked, it flows back to the inside. Sometimes you see water inside, or sometimes it can cause a situation that leads to damp or rotted siding or structural members in that area. It is not a correct practice.
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